Tractor shovel



July 6, 1948. L. BEYERSTEDT? TRACTOR SHOVEL 2 shets-Snee't 1 Filed nec; 12j, -194:5

R. L. BEYERsTED-r July 5e, 194s.

2 Sheets-Sheet 2 Filed Deo. l2. 1946 INVENTOR.

Patented July 6, 1948 f TRACTOR SHOVEL Ralph L. Beyefstedt, Libertyville, nl., assigner to The Frank G. Hough Co., Libertyville, Ill., a corporation of Illinois Application December 12, 1946, Serial No. 715,871

1 Claim.

In the known type of tractor-shovel in which the shovel is mounted at the iront of the tractor on the end of a duplex or single forwardly-extended boom hinged at its .rear end on the tractor and equipped with hydraulic-means for rocking the boom and its loaded shovel upwardly to dumpingposition and for allowing them to swing down to their lowermost digging-position, it has been found that a comparatively simple heretofore undiscovered modication in such construction which results in valuable, novel and advantageous functioning or operating properties may be benecially availed of.

By the employment of4 this innovatory invention, relating more particularly to the means for and manner of operating the boom and its shovel, a graduated accelerated speed of lift of the shovel is obtained whereby in a speciiic instance the time oflift formerly of 10% seconds was reduced or lessened to 81/2 seconds, using the same oilpump for performing the lifting operation.

A further` distinct advantage resulting from the use of the present invention is the attainment of a relatively low rate of lift at the lowest part of the stroke, where it is especially needed for control in grading, whereas a fast rate of lift is secured in the upper part of the stroke, where it is distinctly beneficial in elevating the loads in the shovel over the bodies of trucks into which it is to be delivered or discharged.

A current preferred embodiment of the present invention in physical form," whereby the above-stated and other aims of the invention are attained, has been portrayed in the accompanying drawings, forming a part of this specification,

and has also been described in detail below in order that those persons acquainted with or interested in this art may be informed as to the structural features incorporating the invention and advised as to the attainment of the substantial beneiits and advantages resulting from the use of the invention.

In these drawings:

Figure 1 depicts, with some structural parts omitted, a tractor-shovel equipped with the new( invention, the shovel being shown in its uppermost dumping or discharge position;

Figure 2 depicts inV plan view the boom portion of the appliance;

Figure 3 is a transverse section on line 3--3 of Figure 2, but on a larger scale;

Figure 4 is a perspective view of one of the long links; and

Figure 5 Presents a side elevation of the construction with the various parts of the mechanism in their several positions with the shovel at three diiierent elevations.

vis

By reference to the several views of these drawings, it will be observed that the internal-com'- bustion engine equipped tractor, ydesignated as a whole il, has a forwardly projecting boom I2 of the dual or duplex type, although the invention is equally applicable for satisfactory employment with a single boom, fulcrumed at its -rear end Aon the tractor at I3 and with its parallel members cross-connected together by a back-bar I4, the front ends of the two parts of the boom being also appropriately transversely joined together by a shaft I5 on which the shovel I8 is hinged in the usual manner, the locking'and unlocking means coacting with and controlling the dumping of the shovel not being shown because although employed they form no part of the instant invention.

At an appropriateY point Il intermediate its length each such boom-lever I2 has a hinge-pin mounted thereon and projecting from its opposite sides, the upper portions of a pair of like links I8, I8 of equal length being rockingly supported on each such pin I1. g

The lower portions of each pair of the links I8, I8 are equipped with a hinge-pin I9 rockingly connecting them to the forward bifurcated end of a longer link 2l hinged or fulcrumed at its rear end to thetractor by a pin 22 whose axis'is directly below the axis of fulcrum I3, and at a vertical distance therefrom equal to that between the axes of the elements I1 and I9,^the distance between the axes I3 and I1 and that between the axes 22 and I9 being equal in the present case whereby the stated structure constitutes a parallel-motion mechanism.

To operate each boom-member II2, the usual hydraulic-cylinder 23 and its piston and pistonrod 24 are employed, but, instead of being directly connected to its boom, or to a member fixedly mounted on the boom, the piston-rod 2l is hinged at its forward end on the same pin I9 tothe combined links I8 and 2| by which, means the stated objects and aims of the invention are attained and satisfactorily taken advantage of.

When the boom and shovel are in their bottom or ground position as presented in the lower part of Figure 5, the leverage which the combined cylinder, piston and piston-rod exert. by the oil under suitable pressure entering the cylinder in the usual way, on the boom carrying the load in its shovel is the distance between the axis of fulcrum I3 of the boom and the axis of the cylinder and piston-rod on the line 3 0-30 at a right-1' angle from such fulcrum to the axis 3|-3I of the cylinder and piston-rod at the then position of such axis.

By the time the boom Ihas ascended or rocked upwardly by the hydraulic means to its horizontal position depicted in the middle portion of Figure 5 such leverage has decreased, as shown on line 32, 32 with a corresponding-increase of speed of boom and load lift due to substantially uniform continued feed of oil into the cylinder 23 and corresponding speed of travel of the piston-rod 24.

With the continued acceleration of speed of boom elevation due to the sustained decrease of leverage, when the boom approaches its highest or shovel-discharge position,` the corresponding elements have the relative positions clearly indicated in the upper portion of Figurel 5, the corresponding leverage being indicated by the arrowhead on line 33-33.

This initial low-speed of load-lift and its subsequent rapid increase of speed is a valuable time factor with respect to loading trucks, etc.. and the greatest power is, of course, availed of when it is most needed by the longer leverage during the period the shovel is digging its load at low level.

It will be noted that in the particular instance under consideration links I8 are always vertical and the axes of links 2| are invariably parallel to the axis of the boom, but it is-to be borne in mind that these conditions are not always vital and under certain circumstances modifications may be advantageously employed without departure from the heart and essence of the invention, and without-loss or sacrice of any of its material benefits and advantages.

For example, the distances or lengths between the axes of the parts I'I and I9 and between the axes of the elements I3 and 22 need not always be equal, neither must the axis of part I9 be invariably directly below the axis ofpelement I1, or the axis of part 22 directly vertically in line with that of fulcrum I3, nor must the lengths between the axes of elements 22 and I9 equal the distance between the axes of parts I3 and IT in all instances, or stated somewhat otherwise, the parallelemotion feature is not an indispensable factor in all cases provided the attainment of the main objects of the invention are secured in all instances.

Iclaim:

In the known type of tractor-shovel having a `shovel mounted on an end portion of a boom horizontally fulcrumed at its other end portion on the tractor for swinging movement of the boom and shovel in a vertical plane, an hydraulic-cylinder, piston and piston-rod horizontally hinged at a fixed point on said tractor for rocking movement in a vertical plane, meansto admit iiuid under pressure into said cylinder and to discharge it therefrom to operate said piston, and means operatively connecting the piston-rod to said boom, the novel improvement in said piston-rod connecting means including the combination of a rst vertical link, means hlnging said link at its upper portion on said boom at a point intermediate the length of the latter, a second link, means hinging said second link horizontally at an end portion thereof on said tractor directly below the fulcrum of said boom, means hinging said second link to said first link directly below the hinge of the latter on said boom and at a distance therefrom the same as that between the boom fulcrum and said second link hinge on the tractor, thereby forming a parallel-motion mechanism, and means hinging said piston-roddto said two links coaxially with the means hinging them together. said iirst link remaining always vertical during its entire movementv with the boom to obtain the desired functional advantages of such verticality.

RALPH L. BEYERSTEDT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Ender Dec. 17, 1946 

